c++QT错误怎么解决

D:\3D Printing\QWT\zxin\zxin\Stl-sobel-V6-chuankou\stlfile.cpp:102: error: no match for 'operator<<' (operand types are 'std::basic_ostream' and 'std::ifstream {aka std::basic_ifstream}')
::std::cerr << "The file " << file << " has a wrong size."
几个地方出现这种错误
报错在类似这句话 ::std::cerr << "The file " << file << " has a wrong size."
<< ::std::endl;

file是什么类型，不是int double string等类型的话没有对应的重载函数